Ruminant digestive influences on germination and establishment of prairie plants.

摘要

Using livestock to disperse seeds of tropical and agronomic plant species has been investigated. The objective of this research was to survey a number of North American grassland species for their suitability for "applied endozoochory" using a variety of testing methods.; In phase I, germination characteristics of 42 species were measured after laboratory bovine in vitro digestion. In phase II, seeds of six species from phase I were fed to cattle, to measure responses in vivo and to evaluate the laboratory procedure's reliability. In phase III, Illinois bundleflower [Desmanthus illinoensis (Michx.) MacM.] and sand lovegrass [Eragrostis trichodes (Nutt.) Wood] were seeded using broadcasting and dung pats. A greenhouse dung-pat germination study including weathering and watering treatments also was conducted.; Phase I results indicated that seeds of legume species are more likely to survive digestion than members of other families, and reconfirmed the importance of water-impervious seed reported previously. Phase I and II germination results were consistent for four legumes tested. Two grass species had low survival and percentage germination. Destruction of buffalograss [ Buchloe dactyloides (Nutt.) Engelm.] burs was attributed to rumen- raft retention. Hindgut effects not reproduced in the laboratory procedure apparently killed sand lovegrass seed. In vitro digestion was a good indicator of in vivo response for legumes.; In phase III, sand lovegrass establishment was negligible from both dung and broadcast seedings. Illinois bundleflower germination was negligible until the third growing season. Germination from dung pats then was attributed to seed weathering. Germination from broadcast seedings was attributed to a pre-growing season fire, which breached hard seed lying on the soil surface. Rainfall was abundant in 1998. The beneficial effects of weathering and adequate moisture also were seen in the greenhouse study.; Applied endozoochory is a viable seeding method with some reservations. Neither high populations nor quick establishment of plants should be expected. Recommendations are given for maximizing hard-seed content by selecting for small seed size, a feeding method based on salt regulation, and the optimum application season.